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Questions tagged [wallet-security]

Questions about keeping wallets and e-wallets safe.

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20
votes
3answers
13k views

Is it safe to reuse a Bitcoin address?

Besides the obvious privacy implications, and (according to a bitcointalk.org forum post) the fact that once an address is used your coins that rest on it safety depend entirely on the ECDSA safety (...
17
votes
4answers
6k views

What are the risks of using Strongcoin.com as an online wallet?

Strongcoin claims it is "The Safest way to store your Bitcoins. The only Bitcoin e-wallet service that's not vulnerable to security breaches. Your Bitcoin keys are encrypted in the browser." ...
9
votes
2answers
2k views

How can Trezor update firmware but never receive malware?

I understood from What is it about a Trezor that means it can't be infected by malware? that a Trezor would only interpret data as transaction details, but the Trezor also updates firmware. How is it ...
9
votes
4answers
986 views

I'm new to Bitcoin, how do I keep my bitcoins secure?

With the recent rally and media attention, lots of new people joining the Bitcoin community. A lot are asking: I'm new to Bitcoin, how do I keep my bitcoins secure? and if they aren't that's the ...
8
votes
3answers
3k views

What stops a wallet from stealing bitcoins?

I'm not particularly knowledgeable on the topic of cryptocurrencies so it's possible that I've missed something obvious, but I still wonder what it is that stops a wallet from stealing from you. ...
8
votes
2answers
669 views

Can a closed source wallet ever be completely trust-less?

Open source Bitcoin wallets are clearly in demand for obvious reasons. Users want to know what the code is intended to do and what may be possible. Is it even possible for closed source wallets to ...
6
votes
1answer
17k views

Alert Key Compromised, upgrade required

I just got this message: "Alert key compromised, upgrade required". How urgent is this? Am I in danger of losing my Bitcoin? What do I do?
6
votes
2answers
2k views

BIP32 recommends a 256 bit seed. Why do most Bitcoin wallets only use a 128 bit seed?

According to BIP32's "Master key generation" section, "256 bits is advised". See https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#Master_key_generation Why did BIP32 consider 256 bits ...
6
votes
2answers
5k views

What is the most secure operating system that I can use to store bitcoins without having to fear a hacker stealing them?

What is the most secure operating system that I can use to store bitcoins without having to fear a hacker stealing them?
6
votes
1answer
2k views

Is it really safe to use vanitygen to generate your unique bitcoin address?

I've been wondering if using vanitygen to create your own bitcoin address with a unique prefix, is safe from being compromise by others? I'm currently using a shared wallet address from a trusted ...
6
votes
3answers
3k views

Which exchanges support U2F authentication? [closed]

I got myself a nice security key (Yubico Fido) today, which utilises the U2F protocol. But to my surprise not a single Bitcoin exchange seems to support this yet, only Google itself. So which ...
5
votes
2answers
1k views

Can a clever hacker still steal everyone's money from the blockchain.info wallet?

Blockchain.info claims: We cannot (and don't want to): View your balance View your address book Make transactions on your behalf Confiscate your wallet Lock you into our service. ...
5
votes
3answers
779 views

What did I do wrong that caused me to lose bitcoin?

I've been accumulating bitcoin into a paper wallet for a couple weeks. It's all been stolen. I'm trying to figure out what I did wrong: https://www.blockchain.com/btc/address/...
5
votes
1answer
471 views

Hardware wallet teardowns and side channel attacks

Most of the popular hardware wallets appear to be based on well established open source cryptography. Which hardware wallets have been submitted to extensive teardowns and side channel attack ...
4
votes
3answers
1k views

How can extended public keys generate child public keys without generating the child private key in HD wallets?

According to the documentation on bitcoin.org and the Mastering Bitcoin book, you can use an extended public key to create child public keys in HD wallets by combining the lefthand side of the hash ...
4
votes
3answers
243 views

How can I safely store and trade Bitcoin and other crypto currencies?

How can I safely store Bitcoin? Exchanges require me to deposit to trade, is this safe? If I can't trust exchanges, what is the best way to safely store my cryptocurrency and transact it?
4
votes
1answer
158 views

Would it be wise and extra secure to use non-ascii characters in a brain wallet?

What are some pitfalls if you use non-standard ascii characters in your brainwallet? Say if you were to use asian language characters? Or even extended ascii characters (http://www.theasciicode.com.ar/...
4
votes
5answers
474 views

Store Bitcoins offline

I have some bitcoins and ether at Blockchain.info and I am really scared of losing them. How do I best secure them? Right now I have a paper with the code to restore my wallet, but my coins are still ...
4
votes
2answers
484 views

What multi-sig wallets are there for Android/Jolla?

TL;DR: What wallet apps are there for android (or sailfishOS) that has "true" support for multisig? Requirements/rationale Thinking a bit, if I'm to possess serious amounts of bitcoins, I want a ...
3
votes
3answers
3k views

What can you do with the private key?

I am trying to understand all security regarding blockchain and bitcoins. Let's say you have a bitcoin wallet which is secured, only you know the private key. This bitcoin address was created on one ...
3
votes
4answers
2k views

Is holding funds in a Bitcoin paper wallet safe?

If you received lots of bitcoins, like 100, and you are not comfortable holding them in your personal blockchain wallet, is it preferable to move them and hold them in a paper wallet for safety ...
3
votes
1answer
1k views

My blockchain.info wallet was hacked. How can I create a double send to foil the attacker?

This is the transaction. https://blockchain.info/address/1F8EP97jgQx8QD6XMRg2bCHHrJrZEMUTRt Which is still unconfirmed. I am trying to use https://coinb.in to create a double spend transaction with ...
3
votes
1answer
67 views

Why can't a longer key combat quantum computers?

Google's new quantum computer performed a calculation in 3.5 minutes that would have taken 10,000 years on a normal computer (so they claim: https://www.space.com/quantum-computer-milestone-supremacy....
3
votes
2answers
1k views

Should I put my bitcoin wallet on an encrypted disk or not?

Is it really beneficial to put my bitcoin wallet on an encrypted disk (LUKS encrypted)?
3
votes
2answers
5k views

Bought a used ledger nano s from Amazon / Ebay. How do you factory reset the Ledger Nano S?

I just bought a used ledger nano s from amazon and ebay. What is the best method of wiping this device and factory reset it? What are some other precautions before using this used device?
3
votes
1answer
301 views

How can Bitcoins be sent without Blockchain.info knowing your private key?

Blockchain.info is a hybrid bitcoin wallet with client-side javascript encryption. I understand that the wallet.aes.json where the private keys are stored is encrypted (client-side). But how can ...
3
votes
1answer
2k views

Why one would need *extended* public keys for auditing a bip32 wallet?

(I am reading the bip32 for an altcoin development.) In the bip32 specification, it is written that listing all incoming and outgoing payments of a hierarchical deterministic wallet would required ...
3
votes
1answer
143 views

Is there a hardware wallet project that plans to add multisig capabilities?

What I want: A hardware wallet that I don't need to trust. That wallet will hold one out of three keys in a 2-of-3 multisig scheme. The other two parties will be a paper wallet I create, and a ...
3
votes
1answer
628 views

Is it feasible to derive the root key of an HD wallet from a large sample of child public keys?

I'm considering the following architecture for a bitcoin-related service: A BIP 32 HD wallet is created that controls all of the account keys for the web service. The private key is kept in cold ...
2
votes
2answers
508 views

Is It Possible to Prove Ownership of Public Key Hash without Public Key?

I am building a system where I would like the user to specify a public key hash of a wallet that they have control over in the event of tips, refunds, and/or otherwise needing to send value back to ...
2
votes
2answers
137 views

Who store seed phrases data

Seed phrases seem to be pretty secure, approximately as strong as bitcoin private key according to this site https://en.bitcoin.it/wiki/Seed_phrase. But who store the private key adresses of these ...
2
votes
5answers
2k views

Encrypting wallet manually instead of using hardware wallet

i am new to this community and like to know why one should prefer a hardware wallet instead of using encryption algorithm like AES-256 along with PKDF2 to secure crypto wallets ? i currently hold btc ...
2
votes
3answers
387 views

If the “wallet seed keywords phrase” is all that's needed to restore a hardware Bitcoin wallet, isn't backing that up a nightmare security-wise?

I buy a Trezor. I put all my coins on it. It has me type out the "wallet seed", which is a series of English words in the right order, onto a paper. And maybe I even buy a metallic card ...
2
votes
1answer
129 views

Blockstream Green Wallet Security

I am trying to understand how secure the green wallet is. I thought of a few scenarios where my funds might be in danger: If GreenAddress service becomes unavailable, they have a nlocktime ...
2
votes
2answers
2k views

Using a dedicated phone as “hardware wallet”

Is there anything inherently insecure about using a dedicated Android phone as a "hardware wallet"? A dedicated phone implies: a clean ROM without gapps, e.g. GrapheneOS, Lineage OS without ...
2
votes
1answer
641 views

Are vanity addresses Vanitygen generated really safe to use?

I’m not talking about whether Vanitygen can crack an any existing wallet or not. I know it is practically impossible, considering the computational resources required. But what if, it’s to crack ...
2
votes
1answer
606 views

Are received BTCs really mine?

when somebody send me BTCs I recognize that by seeing a transaction output is equal to my address. But how can I be sure that it's really me and only me who can spend the output? I can check, I can ...
2
votes
1answer
3k views

Can you deposit to an unplugged Trezor?

I just want to confirm if my logic is correct. If I send Bitcoin to my Trezor address while the Trezor is unplugged does the web wallet then receive the private keys from the transaction and only once ...
2
votes
1answer
143 views

Why doesn't the Bitcoin-qt client ask for the Wallet passphrase upon startup?

I've just encrypted my wallet.dat file using the "Settings -> Encrypt Wallet" menu option. I then closed the client and re-opened it. I was expecting to be prompted to put in the wallet password ...
2
votes
1answer
976 views

Security risk(s) in running bitcoin core full node

What are the security risks posed by running a full node bitcoin core client? On a typical system, port 8333 is open and all other nodes can actually 'see' my machine and sites like https://bitnodes....
2
votes
2answers
4k views

How can I recover my MultiBit HD wallet words?

I have problem with MultiBit HD. Its balance changed to an unconfirmed transaction just like in this bug report. It appears that I need to use my wallet words to recover the balance, but I have lost (...
2
votes
1answer
749 views

What is the largest password/passphrase size for a wallet.dat file?

Suppose your wallet.dat file is copied to the wild. I am working on methods for creating very strong (512bits, hopefully much more) passphrases that would make it unfeasible to either use rainbow ...
2
votes
1answer
2k views

Is there any open source implementation of Bitcoin wallet encryption in Java?

I intend to establish an efficient and secure scheme for protection of wallets. For this , I need source code that implements wallet ecryption as mentioned in https://en.bitcoin.it/wiki/...
2
votes
2answers
2k views

How does a Trezor passphrase prevent restoration of a wallet if an attacker knows the seed?

Trezor User Manual says if you forget the passphrase there will be no way to recover your bitcoins. Not even the Recovery seed. How is it that you (or an attacker who knows the seed) can't just ...
2
votes
1answer
656 views

How can a third party spend BCH accidentally sent to a BTC address?

I transferred BCH to an Electrum wallet address and haven't ever received it because Electrum uses only BTC. As I have been trying to recover it, I looked up the transaction on explorer.bitcoin.com ...
2
votes
2answers
1k views

Are my retrieved BCCs stolen from my Electron Cash wallet?

I installed the Electron Cash Wallet on my laptop (version 2.9.2 downloaded from official site "electroncash.org" with the correct checksum). Then I retrieved my BCCs (from an imported BTC adress in ...
2
votes
1answer
908 views

Stealing Bitcoin Private key using Man-in-the-Browser

I was reading that Man-in-the-Browser (MITB) is able to steal credentials data, modify html, and modify out going data. Indeed, MITB is one of the big threat of Bitcoin online wallets usually, when ...
2
votes
1answer
113 views

End-user security measures to protect your Bitcoins [closed]

I am trying to make a presentation on Bitcoin for my Security and Risk Analysis class. Currently, my research question is : What bitcoin security measures can enhance user-protection and reduce theft?...
2
votes
2answers
124 views

Where are statistics data about stolen bitcoins and successful attacks?

I am looking for data about stolen bitcoins. Is somewhere statistics about how many bitcoins were stolen etc.? I only know that bitcoins were stolen in Mt.Gox and Flexicoin...
2
votes
1answer
144 views

How to check that I control an address

I recently created a bunch of bitcoin addresses (public starting with 1, PK starting with 5) from a paper wallet, that I downloaded from their github (https://github.com/walletgeneratornet/...